New main-chain crown-ether polyimides for lithium-ion battery membranes

Thin rugged membranes based on polyimides having a columnar liquid crystal (LC) morphology (nanotubules of crown ether) which rapidly conduct lithium ions between the anode and cathode is the objective. This preliminary report describes the synthesis and characterization of a novel lithium-ion conducting polymer containing crown ether segments in the backbone. Segments of fluorocarbon co-monomers were used to lower cohesive energy density relative to the hydrophilic crown ether segments in order to promote a microphase-separated morphology. However, no evidence of phase separation nor LC morphology are observed. The ionic conductivity of the polymer films was measured using the technique of electrochemical impedance spectroscopy (EIS) and two polished stainless steel electrodes with the polymer film coated on the working electrode